Roadster Supply advertises a front disc brake kit for '37-'41 Ford spindles that states a track width 1" narrower than other disc conversion kits. They're showing "Out Of Stock" on their website and haven't replied my question about them or answered their phone. Does anyone know what they do differently to keep the track width more narrow than other kits from Speedway and others? I have the Speedway Metric caliper kit on the '37-41 spindles on a '33-'36 axle (50.5" kingpin centers) in my Model A coupe and my 185R-15 front tires are out quite far from the centerline crown of the front fenders. Lynn
Here's what my search of their website shows. Is this the kit you are inquiring about? Give them a call about restocking. It would be nice to know how much narrower the kit is from OEM stock. Make sure the inside dia. of your rims will fit. Narrowed 37-41 Ford - GM Caliper Econo Disk Brakes (roadstersupply.com)
I have been looking at a number of these kits, including this one. Where i believe they pick up that 1" has something to do with item #1 in this speedway kit. Speedway indicates this to be a "bearing adapter" for the ford spindle. I will be following this thread to see if I learn more.
Voh, I am unclear as to what you mean the term pick up when you say: " they pick up that 1" has something to do with item #1 in this speedway kit. Does it mean the width is reduced by 1 inch on each side or 1 inch on total wheel mounting distance?
The description says 1". I bet its 1/2" per side. I'm only guessing, but i bet Roadster Supply has created a race/bearing that fist the spindle directly and doesn't need that additional part.
for the extra 150 bucks, buy the finned caliper version BECAUSE the banjo bolt position is in a much better location. note IF you buy either, the rs kit uses a stock gm style m10 banjo the other brand uses a imperial double bubble flare in my opinion if you fit a gm 70-77 rotor onto a 48 inch wide axle AND run a 6j wheel with a 3 5/8ths inch 'back-sapce' you will get a track of 57.25 inches when you fit this narrowed kit, onto a similar 37 inch wide axle, with the exact same 6j by 16 vintique genny wheel its exactly the same 'track as the 70-77 rotor at 57.25 now lets 'summize' that a 6j by 16 vintique genny wheel is actually a 7 inch wide rime, outside to outside, when measuring the back-splash at 3 5/8ths on one inch it would imply that the wheel actually has a positive et of 1/8'' when you fit a volair rotor onto a 46'' wide axle, the wheel mopunting face each side becomes 56.5 so with that said, claiming a track width is meaningless specifying a comparison with something else, as you measure track from the centre of the tyre fitted to the vehicle. you could have MANY differing offset wheels it maybe that, the one is the same as a 70-77 gm rotor and the volaire rotor is a smidge more than 10mm or 3/8ths each side wider. note if you layed the 19mm wide rotor down next to a volaire one , it would measure 1/2'' different;ly across the face. one is an inch and one is 3/4 sweating on the bearing spacer needs to be done with a mapp gas bottle - really so the answer is, fit a narrower axle
For many years I have used Pete & Jake's Power Stoppers because their hub does not require a spacer and retains the stock Ford width. They are more expensive than the Econo kit but higher quality. I have also sold on customer chassis the out of stock brake kit from Roadster Supply with no complaints.
I believe @Voh has got it. Since it says so in their add: "No bearing adapter required - offering a 1" narrower track width"
I'd agree that it seems the bearing adapter not needed is where the difference in width might be, but the large diameter of the adapter is where the seal rides, if I remember correctly when I assembled Speedway's kit on my Model A. If the adapter is eliminated it seems there's no place left for the seal to ride? I'm still baffled. Both of Speedway's kits say in the details that they add 8 1/4" to the width from the spindle kingpin to the wheel mount surface. The example they give is a 48" axle ends up at 56 1/4" on either kit, but one uses Metric calipers and the other uses Intermediate calipers. https://www.speedwaymotors.com/1937...Brake-Kit-5-on-4-3-4-Metric-Caliper,2010.html (uses the cast brackets) and https://www.speedwaymotors.com/1937...ke-Kit-5-on-4-1-2-Metric-w-Spindle,468165.htm (uses brackets cut from plate steel) There is some other front brake kit that Speedway offers that says it widens the track width a bit, so is Roadster Supply maybe comparing to that kit? The one post above refers to the backspace and width of wheels and all I'm curious about is the wheel mount surface width. For some reason I seem to recall that Volare rotors make things wider than GM rotor-based kits. I guess a person could go to a 48" wide or even 46" wide axle to keep everything "tucked", but I'd like to know the details of what Roadster supply is claiming and comparing their kit to. Lynn
I went with the roadster shop kit on my 33 and it did narrow it a inch over all from what my drum brakes were , I went with the finned calipers , all parts fit great and work great , not sure if that helps
Thanks. Good, first-hand information. If there was no press-on adapter for the inner wheel bearing and grease seal, can you share how that was accomplished? Lynn
Looks like I lucked out by ordering a kit a few months ago. I just installed the kit this weekend. They do not use any bearing adapters. The bearing is sized correctly for the spindle. I wanted to keep the 5x5 wheel lugs to use the original wheels. I’m thinking the rotors must be a custom part they have made. No complaints about their kit everything looked like good quality and fit. To get the banjo fitting to exit in the right direction I just filed down the calliper casting to get it pointed in the right direction. I measured the track width and ended up about 58” to the wheel mounting surfaces I seem to have lost my measurement but I seem to remember 57.5”. I think the claim is narrower than the competitions kit. I used the Pete and Jake’s kit on my roadster that required a bearing spacer.
So, as best you might remember, I guess the inner bearing race was sized directly to the Ford spindle diameter and seated by the "step" on the spindle's axle, and then a seal was provided that was small enough inner diameter that it fit the "step" area rather than the larger diameter that is used with kits that have the press-on adapter? I wouldn't ask that you take one side apart to show us, but it would be interesting to see just what they came up with. Perhaps a bit of machining on the inner bearing and seal side of the hub portion of a GM rotor? I'm going to take a close look at the spacing relationship of the rotor's inner face and the caliper bracket compares with the Speedway kit on my Model A using '37-'41 spindles Thanks! Lynn
The thing that is interesting to me is how the bracket, that appears to be the same, works in both conditions (adapter / no adapter)
While I'm not an expert on the RS kit; I believe, as another poster mentioned, the only way they could make it narrower would be to use a custom made rotor. So you would be dependent on a custom made consumable part sometime in the future. Wonder if it would be still available. We have used both Speedway's & ECI's F-150/big GM caliper kit which is slightly narrower than stock Lockheed drums. Uses all stock consumables. These do not hang out there the extra inch or so like the common disc brake kits.
look at a picture of a 7032r raybestost 1975 volaire or charger 11'' rotor look at the hub depth and the rotor friction surfaces then look at a 70-77 chevy rotor these are both 1'' thick rotors and 11'' diameter the volaire has a longer hub and a shorther snout the chevy has a shorter hub and a longer snout. more importantly on these rotors that do not need a spacer, is the bearing seal runs on the stock 37-40 seal bump. the bearing spread is increased - which is MUCH more important and they do 'probably' EXACTLY match the wheel face to wheel face of a 40 ford which all told if you include the ease of the m10 banjo face mount 4 'excellent; reasons why for a few more hundred bucks ------ anyways, they still dont include a dust sheild for a kit that costs that much - so i call 'cobblers' and they 'still' havn't moved in tech evolution to something like a common or garden twin pot caliper from something like a ranger AND the 78 metric caliper is and was never intended to run on an 11 inch disc as they are all 10.5 there was a pic somewhere of a car with some mgbgt dust guards modded to fit a 37 spindle with an 11;; rotor but i cant find int anymore
If the narrow set up does not require the hub spacer, then the bearing needs to seat against the hub. That may be a special bearing. Then with out the hub spacer, the seal needs to cover the gap. That may be a seal that is no longer produced. Bearings and seals used to be able to be both by bought the inside diameter and the outside diameter measurements. That may not be the case anymore. Many of the old sizes are no longer being produced. If the rotor sits a 1/2" closer to the caliper bracket, one would assume that spacing between the bracket and the rotor needs to be changed, or there may have been too much clearance between the rotor and the caliper bracket. The difference in the cost between the narrow and the normal versions could be the offset caliper bracket, the special wheel bearing, and the special grease seal. The bearing and , or the seal, and or the caliper bracket may not be available these days, which is why the narrow set up id not in stock. The 10 1/2" rotors and the 11" rotors and the GM metric calipers is an interesting concept. The difference between the 11" rotor and the 10 1/2" rotor may only be the difference between the bearing race surfaces and to outer diameter of the rotor. One would have to do some measuring, but it is possible the actual brake pad contact surfaces on both rotors are exactly the same. If the caliper mounting bracket is longer, it can safely move the caliper out far enough to clear the outer edge of the rotor. Then the only difference is the width of available brake pads that fit into the caliper compared to the width of the surface area on the rotor the pads contact. It is entirely possible the brake pad contact surface on the 11" rotor and the same brake pad contact area on the 10 1/2" rotor are the same width, but as long as the brake contact surface on the 11" rotor is at lease as big as the contact surface on the 10 1/2" rotor, I see no reason the caliper wouldn't work. If I'm wrong, someone needs to explain to me why a 1/2" larger diameter rotor is going to have a negative effect on a properly re-positioned GM metric caliper.
@hotrodtodd1960 or @Rob28 Did either of you make note of part numbers of the bearings & seals in RS kit you installed.
I contacted Roadster Supply today. They are making some changes to the caliper mount so the spacer between the caliper mount and the spindle won't be necessary any more. The caliper used is the same GM metric as the other kits on the market ( comes from overseas) . I have the AFCO on my coupe so I can reuse it. The man I talked to said the kits 40108 with changes should be available in about a month. He also said the reason for the 1/2 "/side narrow er track width is the elimination of the inner bearing adapter as advertised. FWIW.
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